/Engine/Source/Runtime/Core/Public/GenericPlatform/GenericPlatformMisc.h
If you do not have permission to call this on one or more of your platforms, set GET_DEVICE_ID_UNAVAILABLE=1 in your build step to ensure that any calls that may be made to this API will simply return an empty string.
the unique string generated by this platform for this device, or an empty string if one is not available.
static [FString](API\Runtime\Core\Containers\FString) GetDeviceId()